A manhunt that paralyzed Boston and gripped the nation ended Friday night when police apprehended Dzhokhar Tsarnaev after a shootout in Watertown, Mass. The 19-year-old suspect in Monday’s marathon bombing eluded authorities for more than 12 hours following a fierce firefight with police early Friday morning that left his brother and suspected accomplice, 26-year-old Tamerlan Tsarnaev, dead.

Police cornered the younger Tsarnaev in the backyard of an idyllic white house on Franklin street after combing a 20-block area for most of the day without luck. A tense standoff ensued, as loud bangs rang through the streets and helicopters hovered overhead, Tsarnaev holed up in a boat stored behind the house. At roughly 8:45 p.m., word came over the police scanner: “Suspect in custody.” Tsarnaev, reportedly in serious condition from a gunshot wound, was taken to an area hospital.

The investigation into Monday’s attack, which killed 3 and injured more than 170, escalated quickly. The FBI released photos of the suspects late Thursday in hopes that the public might help identify the grainy pictures of two men believed to have planted pressure cooker bombs near the finish line of the Boston Marathon. By 2 a.m. Friday morning, a MIT campus officer was shot dead and police were chasing the Tsarnaevs through the streets of Watertown, exchanging fire with the suspects as they dropped explosive devices out of the windows of a stolen car. Dzhokhar fled after Tamerlan was killed.

Law enforcement officials and family members identified the brothers as ethnic Chechens who came to the U.S. from Russia. They lived near Boston and had been in the U.S. for about a decade, an uncle said.

Chechnya has been the scene of two wars between Russian forces and separatists since 1994, in which tens of thousands were killed in heavy Russian bombing. That spawned an Islamic insurgency that has carried out deadly bombings in Russia and the region, although not in the West. But investigators have shed no light on the motive for the Boston Marathon bombing and said it was unclear whether any terrorist organizations had a hand in it.

Tamerlan Tsarnaev spent six months in Russia in 2012 and, according to the New York Times, law enforcement officials are retracing his steps to determine if he might have received instructions or training from extremists during that trip. But even before that, the FBI said it interviewed Tamerlan in early 2011 after a foreign government warned U.S. officials that “he was a follower of radical Islam and a strong believer, and that he had changed drastically since 2010…”

The Tsarnaevs’ parents, who are currently in Dagestan, reportedly told Russian state TV that both boys were innocent and possibly “set up.”

As the sun rose Friday, police cordoned off a broad swathe of Watertown, searching house-by-house as officials advised all Boston area residents to remain inside their homes. Around midday, as the manhunt dragged on, the suspects’ uncle Ruslan Tsarni of Montgomery Village, Md., pleaded on television: “Dzhokhar, if you are alive, turn yourself in and ask for forgiveness.”

The search by thousands of law enforcement officers all but paralyzed the Boston area. Officials shut down all mass transit, including Amtrak trains to New York, advised businesses not to open, and warned close to 1 million people in the entire city and some of its suburbs to stay inside and unlock their doors only for uniformed police.Some neighborhoods resembled a military encampment, with officers patrolling with guns drawn and aimed, residents peering nervously from windows and people near surrounded buildings spirited away.

The fear was palpable. Shanti Kapoor, a junior at Boston University who had been staying at friend’s apartment in Watertown, says she was picking up supplies at a 7/11 at Bigelow and Mt Auburn streets early Friday evening when she saw SWAT teams speeding by. “All the cops were running and saying, ‘It’s him! It’s him!'”

When the gunfire finally fell silent, police swept through the scene with dogs to check for bombs. As word spread of the arrest, applause broke out in the crowd that had gathered outside the police cordon. The Boston Police Department declared on Twitter that “Justice has won.”

“I have never loved this city and its people more than I do today. Nothing can defeat the heart of this city .. nothing,” Boston Mayor Tom Menino said in a statement. Massachusetts Governor Deval Patrick expressed relief, surely shared by his constituents, that the ordeal was finally over. “It’s a night when I think we’re all going to rest easy,” he said.

But Boston’s residents didn’t feel much like rest. Glad to be free from fear and a restrictive lockdown, revelers thronged Boston common throughout the night. In Dorchester, where an 8-year-old boy killed in the bombing lived, people set off fireworks. Saturday’s sports games–the Bruins vs. the Penguins and the Red Sox vs. the Royals–turned into scenes of exuberant celebration.

“We’ve closed an important chapter in this tragedy,” President Obama told reporters late Friday night at the White House, before adding that “unanswered questions” — why two men turned on their adopted city and country — remain.

The arrest, rather than the killing, of Dzhokhar Tsarnaev may bring some answers to those questions, as well as closure to citizens of a city that spent a week in shock and terror. Lisa Coveney of Foxboro drove 25 miles to Watertown Friday to see an end to the saga. “I’m glad he’s alive,” she said of Tsarnaev, “because I want to get answers.”

— With reporting by Christina Crapanzano, Jay Newton-Small and Kate Pickert/Watertown, and Zeke J. Miller/Washington; the Associated Press contributed to this report